If you can be a professional dota player, then it is a good choice. You will be paid heftily just by playing your favorite game. So if ever you want to replace gambling with dota, be sure you are a serious player and make it your goal to be a professional player. In that way, even if you are addicted to it, you are earning a lot too.
Well playing games like these maybe will be a great substitution for you addiction in gambling! but getting addicted into something is really bad but being a professional in it and doing it for your country maybe it's half bad well there is now a tournament or these kind of games right now are getting popular and being value in different parts of the country.
it always helps to divert your attention and time to something else instead of gambling if you trying to quit it.
and as a Dota2 player i can tell you that Dota2 is pretty addictive and you can get hooked up real easy and real fast with a lot of fun.